Steam-power plant with closed feed system



March 4, 1930. c. R. LANG swam rowan PLANT WITH QLO'SED FEED SYSTEII Filed Feb. 11, 1928 Patented Mar. 4, 1930 UNITED STATES CHARLES RUSSELL LANG, OF CATHCART, GLASGOW,

SCOTLAND, ASSIGNOB TO ZG.,'&;J'.

WEIR, LIMITED, 01 GLASGOW,- SCOTLAND STEAM-POWER PLANT WITH-CLOSED SYSTEM Application filed February 11, 1928, Serial No. 253,778,, and in Great Britain February 26, 1927.

This invention relates to closed feed systems for steam power plants including a boiler, a boiler-feedpump, a steam engine (which may be a turbine), a main condenser,

5 a water-extraction pump which deals With the feed water obtained by condensation of the steam in the condenser, and discharges this feed water under a pressure above atmosphere into the main feed conduit, whence 0 it passes to the boiler-feed-pump, and including also a reserve feed tank.

In closed feed systems it is desirable, for reasons well known, to avoid the inflow (into the feed system) .of feed water from a tank open to the atmosphere, except in just sufiicient quantity as is required to make up losses.

As the water level in the boiler varies within certain limits, there necessarily results variation in the quantity of water in the rest of the system, and it is necessary to provide for this variation. WVithdrawal from, and discharge back into, an atmospheric tank is objectionable as aforesaid.

In certain steam installations, for example, in high-powersteam ships, there is often no room available for a well or tank of any considerable capacity below the condenser.

A proposal previous to the present one, and

applicable to a steam power plant which includes a boiler, a boiler-feed-pump, a steam engine and a main condenser, involves the employment of a de-aerating chamber which is maintained under the same pressure as that in the main condenser by being connected thereto and the employment of a hotwell at the bottom of this chamber, this hotwell (which might be in an elevated position) serving primarily as a balancing chamber to equalize the differences between the output from the condenser and the demands of the boiler: in this arrangement, make-up feedwater is sprayed into the de-aerating chamber and is supplied from a reserve feed tank through a valve controlled by a float in the hotwell.

Now, in a steam power plant according to the present invention, no separate de-aerating chamber is provided; and make-up feed- 59 water is supplied to the main condenser. A

is admitted to the condenser from the reserve feed tank, and mechanism whereby said valve iscontrolled by the said float so as to be closed with a high position of thefioat and opened by a fall of'the fioat.

--How the inventioncan be carried into ef- 1;

feet will now be'describedby reference to the accompanying drawing which is diagrammatic. The invention will be defined :inithe annexed claim.

is themain turbineza is the 'main condenser: a-is a suction head pump .whi'chpwithdraws I the deed water: from the condenser through the pipe :hand :delivers it .into :the pipe m which leads to the water-extraction pump id :and "has an upwardly-extending branch-nwhich.leadsato the elevated feed reservoir 1". An equilibrium pipe Q) connects together the steam spaces in the reservoir 1" and the steam condenser, so as to maintain the same pressure in the former as in the latter. Except for fiow up or down the pipe at to meet irregularities, the pump d delivers all the feed water into the main feed conduit 8. e is the boiler-feed-pump and w the boiler. 20 is the reserve feed tank.

The reservoir 1" contains a float g which by a suitable mechanism controls a valve f placed on the pipe t which connects the reserve feed tank a with the condenser.

When, due to a reduced delivery of Water into the boiler, the pressure rises in the main feed conduit, and hence in the pipe m, there is a flow of water into the reservoir 1 and, under the opposite conditions, there is a flow from the reservoir 7- into the pipe m. A certain pre-determined range of water level in the reservoir is provided for. When the water level falls below the predetermined low level, the valve f is opened and a flow of 1 00 water takes place from the reserve feed tank into the condenser.

By means of the present invention, therefore, it will be seen that fluctuations in the 5 working of the system are provided for, and Water admitted to the system only whennecessary, and then automatically. c Having thus described my invention, What I claim as new and desire to secure'by Letters Patent is A steam power plant having the feed system arranged as a closed-feed system and including a boiler, a steam engine (which may be a turbine), a main condenser, a main feed conduit, a water-extraction pump which deals with the feed water obtained by condensation of the steam in the said condenser and discharges this feed water under a pressure above atmosphere into the said main 7 feed conduit, 'a boiler feed pump WlliCll'dlS charges the feed water from the said main feed conduit into the said boiler, a reserve feed tank open to the atmosphere, an elevated feed reservoir, means for maintaining the said elevated feed reservoir under the same pressure as existent in the said condenser, a pipe connecting the said reservoir-below the water lever therein-with the suction of the said water-extraction pump, this pipe serving as means for to-and-fro movement of feed water between the said reservoir and the suction of the said pump, a float in the said reservoir, apipe connecting the said condenser with the said reserve feed tank, a valve on this lastmentionedrpipe, and mechanism whereby the said valve is controlled-by the said float so as to be closed with a high position of the float and opened by a fall of the oat. I hereby sigxn my name to this specification.

CH RLES RUSSELL LANG. 

